Tubular reaction furnaces are known in which the reaction tubes arranged in the firing chamber form registers or bundles. The tubes can be filled with a catalyst or packing to control the chemical reaction. Normally, the tubes are arranged vertically in the firing chamber such that they can be filled with a catalyst in a proper and uniform manner. In this configuration, upper and lower ends of the tubes can be supported. According to other designs, the upper end is suspended or the lower end is supported while the free ends of the tubes penetrate the firing chamber. Both designs prevent, for instance, thermal stress. The reaction fluid is piped to the reaction tubes via a header system and withdrawn from the tube ends via a product gas header.
According to the traditional design, the reaction tubes are fixed at one end to compensate for tube elongation caused by thermal expansion. In order to fix the position of the reaction tubes in the furnace, the upper and lower ends are arranged such that the tubes cannot move horizontally.
Tubular reaction furnaces have, so far, only been installed ashore. In this case, horizontal dynamic forces do not act on the tube registers during furnace operation. When such reaction furnaces are installed on floating carriers such as floating plant platforms, the structure must withstand static as well as horizontal dynamic loads caused by the sea or storms. The tube length of 10 to 14 m and the additional weight of the catalyst cause bending stresses which act on the reaction tubes during furnace operation. It is therefore necessary to design the tubes for such loads, but the wall thickness involved in conjunction with the required tube length will result in on-stream times that are insufficiently long.